First study finds CBN improves sleep without intoxicating effects

Research by scientists at the University of Sydney is the first to use objective measures to show the component, known as cannabinol (CBN), increases sleep in an animal study. Their findings have been published in the journal Neuropsychopharmacology.

CBN is an end-product of the main intoxicating constituent of cannabis, delta9-tetrahydrocannabinol (THC). 

THC in cannabis is slowly converted to CBN over time, which means older cannabis contains higher levels of this compound. It has been suggested that the consumption of older cannabis is associated with a sleepier cannabis “high”.

In the US highly purified CBN products are being sold as sleep aids, but there has been little high-quality scientific evidence to support this application to date. 

The research team at the Lambert Initiative for Cannabinoid Therapeutics tested the effects of purified CBN on sleep in rats. 

Using high-tech monitoring, the experiments provided insights into the rats’ sleep patterns including the amount of non-rapid eye movement (NREM) and rapid eye movement (REM) sleep.

NREM is deep sleep that promotes physical recovery and strengthens memories, while REM sleep is associated with dreaming and processing of emoti“For decades, cannabis folklore has suggested that aged cannabis makes consumers sleepy via the build-up of CBN, however there was no convincing evidence for this,” said lead author on the study Professor Jonathon Arnold, Director of Preclinical Research, at the Lambert Initiative for Cannabinoid Therapeutics and the Sydney Pharmacy School.

“Our study provides the first objective evidence that CBN increases sleep, at least in rats, by modifying the architecture of sleep in a beneficial way.”

Professor Arnold added: “CBN was found to increase both NREM and REM sleep, leading to increased total sleep time, with a comparable effect to the known sleep drug zolpidem.”

According to the author, unlike its parent molecule THC, CBN did not appear to intoxicate rats. 

While THC’s effects are caused by activating the CB1 cannabinoid receptors, which are present in the brain, the study showed that unlike THC, CBN only weakly activates these receptors. 

The researchers also found that a metabolite [a chemical produced via the metabolism of a larger molecule in the body] of CBN had significant effects on cannabinoid CB1 receptors.

The 11-OH CBN metabolite had some impact on sleep architecture, which might contribute to the overall effects of CBN on sleep.

“This provides the first evidence that CBN indeed increases sleep using objective sleep measures. It was a surprise that CBN metabolism in the body can yield a much greater effect on cannabinoid CB1 receptors than the parent molecule CBN, which has much more limited activity,” Professor Arnold said.

“At this stage our results are confined to testing in rats. Further research is needed to see if this translates to humans.”